In recent years, alcohol (ALC) use and abuse by adolescents has been rising at an alarming rate. Whether ALC consumption during prepubertal years affects specific hormones and the process of sexual maturation is not known. This study used immature female rhesus macaques to assess the effects of ALC consumption on the circulating levels of critical hormones known to be involved in the pubertal process. Ten monkeys averaging 20.28 (?0.3) months of age were bled by saphenous vein puncture at 8:30 a.m. and 8:30 p.m. each day for five consecutive days to determine the baseline, initial levels of growth hormone(GH), insulin-like growth factor-1 (IGF-1), follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and leptin. For the next 12 months, each day at 1:40 p.m., five monkeys were administered ALC (2g/kg) and five monkeys were administered an isocaloric sucrose solution via a nasogastric approach. Blood samples were collected again at 24, 28 and 32 mo nths for subsequent hormone analysis. Food consumption and weight gain were similar for ALC-treated and control animals. The night-related increase in serum GH levels that occurs during late juvenile development (28-32 months of age) in control animals was suppressed in the ALC-treated animals. This action was paralleled by a depression in the serum levels of IGF-1, a peptide recently shown to facilitate the onset of puberty in both rodents and non-human primates. Importantly, serum levels of LH and E2 were so depressed during development by the ALC, with the lowest levels at 32 months. Serum FSH and leptin levels were not altered by ALC. These results demonstrate the detrimental effects of ALC on the activation of hormone secretion that accompanies the initiation of puberty in female rhesus monkeys. Also, they suggest the subsequent growth spurt and normal timing or progression of puberty may be at risk in human adolescents and teenagers consuming even relatively moderate amoun ts of ALC on a regular basis. FUNDING Subcontract with Texas A&M University PUBLICATIONS None